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Sherardizing
Published in Frank Porter, Zinc Handbook, 1991
Sherardizing is a cementation or diffusion process in which previously fabricated articles are first cleaned and then placed in a sealed drum with zinc dust and sand. The process is mainly used on ferrous parts but can be used on copper-based materials. The drum is rotated in a furnace maintained at a temperature below the melting point of zinc 419∘C. Because the mechanism of the formation of the coating has not been completely explained, experience is necessary in carrying out the process. Modified processes should be treated with caution, as results may be inconsistent or unsatisfactory.
Finite element simulation of sherardising concentration field
Published in Transactions of the IMF, 2020
J. Long, X. Li, Y. Zhong, Y. Zhang
Sherardising is a heat treatment process in which zinc is absorbed into the surface of a steel workpiece to obtain a uniform zinc–iron alloy coating. Compared to electrogalvanising and hot dip plating,1 sherardising is simple and environmentally friendly. The coating obtained by sherardising is uniform and smooth, and has high bonding strength with the steel substrate. Its corrosion resistance is good and there is no hydrogen embrittlement.2,3 However, the disadvantages of the process are also obvious, such as it takes a long time to complete the process and the production efficiency is relatively low. In the process of sherardising, the ideal thickness, texture and structure of the Fe-Zn coating can increase productivity. Thus, it is very important to use a modelling technique such as finite-element simulation for the optimisation of the process of sherardising. D. Wortelen4 and Gao Haiyun5 established a numerical model to predict the diffusion process of sherardising by the finite difference method. The difference is used to replace the partial derivative, and the partial differential equation is directly transformed into an algebra problem, which is intuitive, simple to understand, and easy to program. However, the finite difference method is not suitable for dealing with engineering problems with complex boundary conditions. While the finite element method can simulate infinite complexes with finite and interrelated elements, and is currently widely used for carburising,6 nitriding7 and boriding,8 this method has not been applied to sherardising. Therefore, this paper will simulate the influence of temperature and time on the sherardising process by the finite element method, and explore the best temperature and time of the process in order to shorten the production process development cycle and reduce costs.